TY - JOUR
T1 - Aerosol-cloud-climate cooling overestimated by ship-track data
AU - Glassmeier, Franziska
AU - Hoffmann, Fabian
AU - Johnson, Jill S.
AU - Yamaguchi, Takanobu
AU - Carslaw, Ken S.
AU - Feingold, Graham
N1 - Accepted Author Manuscript
PY - 2021
Y1 - 2021
N2 - The effect of anthropogenic aerosol on the reflectivity of stratocumulus cloud decks through changes in cloud amount is a major uncertainty in climate projections. In frequently occurring nonprecipitating stratocumulus, cloud amount can decrease through aerosol-enhanced cloud-top mixing. The climatological relevance of this effect is debated because ship exhaust only marginally reduces stratocumulus amount. By comparing detailed numerical simulations with satellite analyses, we show that ship-track studies cannot be generalized to estimate the climatological forcing of anthropogenic aerosol. The ship track-derived sensitivity of the radiative effect of nonprecipitating stratocumulus to aerosol overestimates their cooling effect by up to 200%. The offsetting warming effect of decreasing stratocumulus amount needs to be taken into account if we are to constrain the cloud-mediated radiative forcing of anthropogenic aerosol.
AB - The effect of anthropogenic aerosol on the reflectivity of stratocumulus cloud decks through changes in cloud amount is a major uncertainty in climate projections. In frequently occurring nonprecipitating stratocumulus, cloud amount can decrease through aerosol-enhanced cloud-top mixing. The climatological relevance of this effect is debated because ship exhaust only marginally reduces stratocumulus amount. By comparing detailed numerical simulations with satellite analyses, we show that ship-track studies cannot be generalized to estimate the climatological forcing of anthropogenic aerosol. The ship track-derived sensitivity of the radiative effect of nonprecipitating stratocumulus to aerosol overestimates their cooling effect by up to 200%. The offsetting warming effect of decreasing stratocumulus amount needs to be taken into account if we are to constrain the cloud-mediated radiative forcing of anthropogenic aerosol.
UR - http://www.scopus.com/inward/record.url?scp=85100495384&partnerID=8YFLogxK
UR - https://www.science.org/doi/suppl/10.1126/science.abd3980/suppl_file/abd3980_glassmeier_sm.pdf
U2 - 10.1126/science.abd3980
DO - 10.1126/science.abd3980
M3 - Article
C2 - 33510021
AN - SCOPUS:85100495384
SN - 0036-8075
VL - 371
SP - 485
EP - 489
JO - Science
JF - Science
IS - 6528
ER -